Filament for audions.



A. McL. NlCOLSON.

FlLAMENT FOR AUDIONS. APPLICATION man IU'NE 6.1914.

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LEXANDEE McLIElAN NICOLSON, or TAEEYTQWN, NEW YORK, .ASSIGNOZR. TO WESTERN COMPANY, OF NEW YORK, N. Y., A CORPORATION OF ILLINOIS.

EIEAMEET FOR AUDIQNS.

To al l wh om it may concern:

Be it lmown that I, ALEXANDER MCLEAN I Nioonsolv, a subject of the King of Great Britain, residing at Tarrytown,. in the" county'ofVVestchester and State of New- York, have inventedcertain new and useful Improvements in Filaments for Audions, of

which-the following: is a full, clear, concise, ,andexact description. v

' This, inventionrelates to filaments suitable '-.for audions, and-its'objects are to provide a filament having great durability and elasticity, having the maximum surface area for the-j'amount'of-material, and which will require the least amount of current for maintaining-it'in ag state of incandescence.

With. the above named objects in view the invention consists in a thin ribbon of platinum or other suitable metal in twisted form. In practice aribbon having a width of three-tenfhs of a millimeter and a thickness. of five=one hundredths of a millimeter has beenfound to be highly eificient. Such --'a. twisted ribbon. filament is elastic. Its

spiral grooveprovides a goodsurface for holding.theactivecoating, such as an oxid eoatmg',-'givensuch filaments. The twisting operation tends to shorten the length of the flatribbon; material. .Hence, to obtain a length.'offlatmaterial is required. Furthermore, contiguous surfaces of the filament are 'givenilength. of twisted filament, a greater fibroiightblos'er together and there is less free -j ';heat-- radiation because of the mutual absorp- 335. Thus,'fa;.-.large surface area having a low heat radiation is provided, and hence a- .amount of current is required for maintaining' the filament in a state of incandescnce.

JtionKof -f raysby the contiguous surfaces.

Specification of Letters Patent. I Patented Apr. 2'2, 1915..

Application filed June 6, 1914. Serial N o. 84.3,504. I

In the accompanying drawings, Figurel shows, on an enlarged scale, the ribbon prior to its being twisted into shape; Fig. 2 shows, I on an enlarged scale, the filament in its twisted form; and Fig. 3 is a perspective view of an audion provided with the filament of this invention. a Like letters of reference refer to like in the several figures of the drawing.

In the said drawings, 1 is a narrow, thin ribbon of metal, suitable for use in making the filament. Said ribbon is twisted inanyi suitable manner to form the filament 2. Said filament has a continuous groove 3,

which as hereinbefore stated provides agood surface for holding an oxid coating and-byreason of the mutual radiation of heat ,between the adjacent surfaces of the groove' tends to hold its heat. It is also obvious that the twisted filament of this invention hasa relatively large active area. What is claimed is: f

1. An audion filament consisting of atwisted metallic ribbon having I an oxid" coating.

twistedcoating.

vided with a spiral groove, and an electron emitting coating upon the groovedportion I of the filament.

an audion,.a metallic filament pro 7Q In witness whereof, I hereunto subscribe my name this 3 day of June Aj. D., 191 i, i

v Witnesses:

E. EDLEB, K. L. STAHL.

ALEXANDER Mam mjcoisoitf} 

